Haven't tried morning EMH yet, though I think it would be great. Evening EMH at MGM was fine, very quiet; Epcot was much more crowded.
MK was open late when we were there, and after the first Spectromagic and Wishes, the park just emptied. We hit the Haunted Mansion and stopped a few places. It was our first night, and still trying to get oriented. On our way up, the crowds were building on MS for the 2nd Spectromagic, but it was a lot lighter than when we had arrived earlier that evening.